GPT and Decreased total leukocyte count: As shown in Table 5 (step 2), after backward logistic regression, the predictive factors for the occurrence of the MTX-related grade 3/4 leukopenia were WBC [odds ratio (OR): 0.786, 95% CI: 0.690–0.894, P = 0.000], RBC (OR: 0.247, 95% CI: 0.151–0.393, P = 0.000), ALT ratio (OR: 1.507, 95% CI: 1.178–1.984, P = 0.002), risk-HR (OR: 65.823, 95% CI: 16.323–21.909, P = 0.000), and rs2114358 GA+AA (OR: 2.308, 95% CI: 1.129–4.372, P = 0.010).